Fibaro RGBW 2 dimmer: 6 dimmers/levels?

I’m using a Fibaro RGBW dimmer 2. Installed at HA it showes 6 dimmers/ levels?
There is only R G B W => 4 dimmers/levels needed to control?
I did search on internet but didn’t find the answers?
What are these 6 dimmers doing (instead of 4?)?